Tensile cracks can shatter classical speed limits

Wang, Meng; Shi, Songlin; Fineberg, Jay

doi:10.1126/science.adg7693

Cited by 14 publications

(4 citation statements)

References 40 publications

(52 reference statements)

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“…1c) in a way that is different from the supershear transition of Mode II elastic ruptures 5, 40 . In addition, the simulations in this study do not produce observable oscillations in the supershear speed regime, which has been reported only for tensile cracks 18,24 . This may be because, in the simulations of frictional ruptures, the preexisting fault, which has a weaker strength than the surrounding media, inhibits the oscillations of supershear speeds, a configuration analogous to imprinting weak layers in tensile crack experiments 18 .…”

Section: Continuum Of Terminal Speeds Produced By Viscoelasticitycontrasting

confidence: 38%

“…Experiments with viscoelastic materials were conducted to demonstrate that tensile cracks [16][17][18] can surpass the S-wave speed and that frictional ruptures 19 in Mode II can surpass the P-wave speed. In addition, unbounded rupture speeds have also been reported in 2D simulations of hyperelastic materials [20][21][22][23][24] , where small scales of hyperelasticity can play a crucial role in dynamic rupture propagation.…”

Section: Earthquake Ruptures In Viscoelasticity Unbounded By Classica...mentioning

confidence: 99%

“…4). Poly(methylmethacrylate) (PMMA), elastomers, and polyacrylamide gels have also been reported [17][18][19] to have viscoelastic properties in laboratory experiments. Since viscoelasticity is a common feature in both geological rocks and engineering materials, their effects on dynamic fracture mechanics should be considered even when their geometrical lengths are short compared to other fault dimensions (Fig.…”

Section: Finite Thickness Of the Viscoelastic Layermentioning

confidence: 99%

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Earthquake ruptures in viscoelasticity unbounded by classical speed limits

Weng

2024

Preprint

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Classical theories using linear elasticity predict that crack propagation is bounded by a limiting speed, beyond which the energy balance becomes unphysical. Recent experiments in viscoelastic materials demonstrated that both tensile and frictional crack propagation can exceed classical speed limits. However, the fundamental physics governing unbounded rupture speeds are still unclear. In this paper, we show via numerical simulations that frictional ruptures in viscoelasticity can propagate at a continuum of terminal speeds that are not bounded by the classical speed limit. All simulated rupture speeds are predicted by the newly developed theory of fracture mechanics incorporating viscoelasticity via the principle of energy balance. In addition to the ratio of the fracture energy to the static energy release rate that can be used to uniquely predict the rupture propagation in linear elasticity, the scales of characteristic lengths in viscoelasticity also govern the energy balance. Beyond the classical speed limit, the energy balance becomes independent of any macroscopic length and is controlled only by the local properties around the rupture tip. These numerical and theoretical findings fundamentally advance our understanding of dynamic rupture propagation.

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Section: Continuum Of Terminal Speeds Produced By Viscoelasticitycontrasting

confidence: 38%

Section: Earthquake Ruptures In Viscoelasticity Unbounded By Classica...mentioning

confidence: 99%

Section: Finite Thickness Of the Viscoelastic Layermentioning

confidence: 99%

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Earthquake ruptures in viscoelasticity unbounded by classical speed limits

Weng

2024

Preprint

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“…Additionally, even though hydrogel phantoms are less heterogeneous than brain tissue, they possess similar nonlinear hyperelastic behavior as in tissues, which will significantly affect the cracking phenomena within them. Recently, the emergence of super-shear cracks in brittle hydrogels induced by tensile forces has challenged classical fracture mechanics, reshaping the fundamental understanding of fracture dynamics [28,29]. In neural engineering, the emergence of cracks and fractures during insertion procedures, particularly those leading to vasculature disruption, poses significant risks that could potentially lead to the cessation of electrophysiological responses and profound chronic immune reactions [30].…”

Section: Introductionmentioning

confidence: 99%

Cracking modes and force dynamics in the insertion of neural probes into hydrogel brain phantom

Li,

Jang,

Shin

et al. 2024

J. Neural Eng.

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Objective. The insertion of penetrating neural probes into the brain is crucial for advancing neuroscience, yet it involves various inherent risks. Prototype probes are typically inserted into hydrogel-based brain phantoms and the mechanical responses are analyzed in order to inform the insertion mechanics during in vivo implantation. However, the underlying mechanism of the insertion dynamics of neural probes in hydrogel brain phantoms, particularly the phenomenon of cracking, remains insufficiently understood. This knowledge gap leads to misinterpretations and discrepancies when comparing results obtained from phantom studies to those observed under the in vivo conditions. This study aims to elucidate the impact of probe sharpness and dimensions on the cracking mechanisms and insertion dynamics characterized during the insertion of probes in hydrogel phantoms. Approach. The insertion of dummy probes with different shank shapes defined by the tip angle, width, and thickness is systematically studied. The insertion-induced cracks in the transparent hydrogel were accentuated by an immiscible dye, tracked by in situ imaging, and the corresponding insertion force was recorded. Three-dimensional finite element analysis models were developed to obtain the contact stress between the probe tip and the phantom. Main results. The findings reveal a dual pattern: for sharp, slender probes, the insertion forces remain consistently low during the insertion process, owing to continuously propagating straight cracks that align with the insertion direction. In contrast, blunt, thick probes induce large forces that increase rapidly with escalating insertion depth, mainly due to the formation of branched crack with a conical cracking surface, and the subsequent internal compression. This interpretation challenges the traditional understanding that neglects the difference in the cracking modes and regards increased frictional force as the sole factor contributing to higher insertion forces. The critical probe sharpness factors separating straight and branched cracking is identified experimentally, and a preliminary explanation of the transition between the two cracking modes is derived from three-dimensional finite element analysis. Significance. This study presents, for the first time, the mechanism underlying two distinct cracking modes during the insertion of neural probes into hydrogel brain phantoms. The correlations between the cracking modes and the insertion force dynamics, as well as the effects of the probe sharpness were established, offering insights into the design of neural probes via phantom studies and informing future investigations into cracking phenomena in brain tissue during probe implantations.

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Tough, Waterproofing, and Sustainable Bio‐Adhesive Inspired by the Dragonfly Wing

Zhou,

Luo,

Jing

et al. 2024

Adv Funct Materials

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The development of multifunctional bio‐adhesive plays a critical role in achieving a sustainable society, where the intrinsic sensitivity to water and poor dynamics severely bottlenecks its scale‐up application. Inspired by the microstructure of dragonfly wings, a strong and tough adhesive with excellent reprocessability is designed and developed by creating a dynamic network consisting of a lignin polyurea (LPU) framework with soybean protein (SP). The LPU framework act as the rigid nervures to slow crack propagation and transfer stress, while the SP dissipate the strain energy through the interplay from the graded hydrogen and imine bonds generated between LPU and SP. The bio‐adhesive achieves significant enhancements in fracture toughness and water resistance by ≈7 and 23 folds, respectively, compared with SP. Furthermore, the capacity for diffusion and restoration of dynamic network endows the adhesive with superior reprocessability, enabling recycled particleboard to achieve high retention of modules (over 80%). This sustainable bio‐adhesive approach offers a promising eco‐friendly alternative to the conventional petrochemical adhesive.

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Tensile cracks can shatter classical speed limits

Cited by 14 publications

References 40 publications

Earthquake ruptures in viscoelasticity unbounded by classical speed limits

Earthquake ruptures in viscoelasticity unbounded by classical speed limits

Cracking modes and force dynamics in the insertion of neural probes into hydrogel brain phantom

Tough, Waterproofing, and Sustainable Bio‐Adhesive Inspired by the Dragonfly Wing

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